1. Field of the Invention
This invention relates generally to a method for constructing and revising road maps and, more particularly, to a method for adaptively constructing and revising road maps in a vehicle navigation system based on vehicle location and previous vehicle travel.
2. Discussion of the Related Art
State of the art vehicles sometimes employ GPS receivers and a map database to identify the location of the vehicle and use the map database in a navigation system to allow the driver to identify his location on a roadway system, and provide directional assistance to a destination. It has been proposed in the art to use the information from previous vehicle travel in such a system to identify a projected vehicle path based on previous driving history. This information can then be used to help the driver navigate along that path, such as to provide traffic congestion locations, construction locations, etc., so as to allow the vehicle operator to know the circumstances of his travel, and possibly change his route based on those circumstances. Current methods for providing information to such systems that determine traffic congestion and the like typically rely on sensors in the road and other structures along the road to provide traffic volume, which can be downloaded by a vehicle.
U.S. patent application Ser. No. 11/372,721, titled Traffic Notification System For Reporting Traffic Anomalies Based On Historic Probe Vehicle Data, filed Mar. 10, 2006 by VanBuer et al., discloses a system and method that employs GPS to track a vehicle path, and use vehicle speed to determine whether certain areas along the path are at normal traffic speeds and volumes based on past driving history. Therefore, by keeping a database in the vehicle itself, patterns can be developed for the same routes that the vehicle travels to identify when traffic conditions may not be normal.